Air heater for furnaces



April 1926.

H. A. IVES AIR HEATER FOR FURNACES Filed. Dec. 27. 1924 l atented Apr. 6 1926.

UNITED STATES PATENT OFFICE.

HARRY A. IVES, 0F BROOKLYN, NEW YORK, ASSIGNOR TO THRIFT FUEL SAVER COR- PORATION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

AIR HEATER FURNACES.

Application filed December 27, 1924. Serial No. 758,327.

To all whom it may concern:

Be it known that I, HARRY A. Ivns, a citizen of the United States, residing at Brooklyn, New York, in the county of Kings and State of New York, have invented certain new and useful Improvements in Air Heaters for Furnaces, of which the following is a specification.

This invention relates to air heaters for furnaces, and especially to a heating device which may be attached to various types of furnace doors, an object of the invention being to provide an improved air heating attachment which will be simplified in con struction, relatively cheap and inexpensive to manufacture, adapted to be readily applied to any standard type of furnace door, and wherein the improved construction is such that the air entering the damper in the furnace door will be heated to a higher degree and at the same time without any substantial obstruction to the passage of the air through the heater into the furnace.

A further object of this invention is to provide an improved air heater adapted to be attached to a furnace door and wherein the heater comprises an inclosing casing having a series of pipes or tubes extending vertically through the heater, the construction being such that the hot gases from the combustion chamber will pass vertically through the pipes or tubes in the heater so that the air entering the damper in the furnace door will contact with these heated pipes thereby enabling the air passing through the heater into the combustion chamber to be heated to the desired extent and at the same time without materially reducing the velocity of the air passing through the heater.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification, wherein like reference characters designate corresponding parts in the several views, and wherein Fig. 1 is a vertical section through the furnace door and heater; Fig. 2 is a sectional view taken substantially on lines 22 of Fig. 1 in the direction of the arrows; Fig. 3 is a sectional plan view taken substantially on lines 33 of Fig. l; and Fig. 4 is a top plan view showing thetop plate of the heater.

Before explaining in detail the present improvement and mode of operation thereof,

I desire to have it understood that the i 1 vention is not limited to the details of construction and arrangement of parts which are illustrated in the accompanying drawings, since the invention is capable of other embodiments, and that the phraseology' which I employ is for the purpose of description and not of limitation.

The purpose of the present improved heating device is to facilitate combustion within the combustion chamber of the furnace and to reduce the consumption of fuel bypreheating the air passing through the damper of the furnace door into the combustion chamber, thus facilitating the mixing of the air with the hot gases within the fur nace. Heretofore in the usual types of heaters for furnaces it has been attempted to increase the heated surface against which the incoming air from the damper contacts by directing the air through a large and cir' furnace door wide open the volume of incommg air was small and usually inadequate. In addition to the fact that such heaters supplied an inadequate amount of air to the combustion chamber of the furnace, the construction thereof was necessarily expensive and complicated, which proved to be a serious commercial disadvantage. The foregomg disadvantages have been overcome by virtue of thepresent invention, wherein the air may be heated to a higher temperature and without materially decreasing the velocity of the air, and wherein the construction is simplified and adapted to be utilized with various types of furnaces.

Referring to the drawings, wherein a present preferred form of my invention 1S shown, it will be seen that the heating device comprises top and bottom plates or members 9 and 10, which are preferably identical in construction and therefore in terchangeable when assembling the parts of the heater. The top plate 9 is provided with a series of holes or perforations 11 and in like manner the bottom plate 10 is provided with a series of holes or perforations l2 similarly arranged so that when the top and bottom plates or members are located in position the corresponding holes or perforations of each plate will be vertically alined. The plates 9 and 10 around the marginal edges thereof are provided with projecting ribs or flanges 13 and lat respectively. The top plate 9 is provided with a continuous groove 15 adjacent to the flange or rib 13, and the bottom 10 is provided with a similar groove 16.

The top and bottom members 9 and 10 are connected together by means of a casing member 17 which in the present instanceforms a continuous vertical enclosing wall. The side enclosure or casing 17 may be formed of sheet metal, and as shown in the present instance is bent into substantially U-shape so that the upper edge thereof will fit into the groove 15 in the top plate 9 and the lower edge. will fit. into the groove 16 in the bottom plate 10. The outer end of the casing is provided with a suitable vent or opening 18 through which the heated air enters the combustion chamber of the furnace a depending lip 19 being provided in the present instance to direct the air downwardly into the chamber. As will be seen from the construction the inner end of the casing is open and improved means is provided for releasably attaching the heater to the inner side of the furnace door 20.

it relatively narrow strap or plate 21 is bent at the opposite ends to pro ide flanges which are riveted at- 28 to the opposite inner faces of the member 1'7. This strap 2 extends transversely across the inner end of the heater and is located intermediate the top and bottom of the heater as shown clearly in the drawings, and the strap 21 is offset or bent inwardly at away from the damper of the furnace door. An attaching strap 25 is also applied to the outer side of the furnace door 20, this strap or plate having the ends 26 bent so as to lie flush against the vertical face of the door and having the central part offset or bent outwardly at 27 in a manner similar to the olfset of attaching strap 21. i-r bolt 28 is inserted through openings in the damper and furnace door and through alined holes in the straps 21 and 25, and by tightening the nut 29 on the outer end of the bolt the straps '21 and 25 may be drawn together and clamped firmly against the opposite faces of the furnace door. The central oppositely bent portions of the straps 21 and have considerable spring or resiliency, so that when the nut 29 is tightened on bolt 28 the straps will be clamped against the faces of the furnace door under tension, thereby firmly securing the heater to the inner face of the door. b'ince the boltin may be inserted through the usual openings in the damper of the furnace door it not necessary to provide any special construction as heretofore in order to attach the heater to the door. The oliset portions of the straps 21 and 25 enable the heater to be ell'ectively clamped on to the door under tension so that it will not be displaced, and these olfset portions furthermore by being spaced from the damper do not obstruct the passage of air through the openings 3U.

\v'ithin the heater casing are located a series of pipes or tubes 31. Each pipe is fitted into a pair of alined openings or holes it and 12 in the top and bottom plates 9 and it). in the present instanc by way of example, the edges of each opening ll. and 12 are beveled off, and the opposite ends of the pipes or tubes 31 are also beveled so as to lit into the openings or perforations, as clearly shown in F 1.

From the foregoing it will be seen that the heater is releasably attached to the inner side of the 'l'urnaee door it), the latter being hinged at to the front wall l of the l. The hot gases will thus heat the es o that the air passing through 30 in the damper and through the heater will contact with the hot walls of the pipes and become heated and will pass out through the vent is into the combustion chamber. It will be particularly noted that the present construction enables the greatutilization of the heat from the hot gases to be obtainet since the number of pipes Ill may be proportionately increased toward tl e outer end of the heater. Thus. as shown particularly in Fig. a larger number of pipes in proportion to the area is provided at the outer end of the heater than at the inner nd, at which point the volume of hot gases rising from the fuel bed is greatest and at the same time hottest. lr rofn this it will be seen that the air entering through the damper may be 'rzulually and increasingly heated as it pas through the heater. At the same time the velocity of the air assing through the heater is not dtarrrascd '0 any material extent. 3sshown by the rro in Fig. 3 the air passing through the ieater will be divided into a ries of thin treains which will be quickly heated to a high temperature by contact with tl e pipes located in staggered relation.

It is to be understood that by describing Hlll - in detail herein any particular form, structure or arrangement, it is not intended to -Having-thus explained the nature of my said invention and described a way of constructing and making the same, although without attempting to set forth all of the forms in which it may be made, or all of the modes of its use, I claim:

1. An air heater adapted for attachment =to a furnace door having a damper and comprising a casing having an air inlet mouth and an exit for heated air and provided with a transverse passage for the hot furnace gases, and means including resilient means for connecting the casing to the door with the front end of said casing embracing the damper.

2. An air heater adaptedfor attachment to a furnace door having a damper and comprising a casing having an air inlet mouth and an exit for heated air and provided with a transverse passage for the hot furnace gases, and means including a resilient clamping member for connecting the casing to the furnace door with the front end of said casing embracing the damper.

3. The combination with a furnace door having a damper opening of an air heater, said heater comprising a casing having an air outlet and terminating at one end in an air inlet mouth embracing said damper opening, means for conducting the hot furnace gases. through said casing, a spring clamping member housed within said casing and secured thereto, and a bolt connected to said member and extending through said damper opening for detachably connecting the casing to said door.

4:- The combination with a furnace door of a heater comprising a casing having top and bottom members provided with pairs of vertically alined holes, pipes extending through the casing, each pipe having the ends thereof opening into each alined pair of holes, and means for connecting said heater to the furnace door, the outer end of the heater having a proportionately larger number of pipes than the inner end.

5. The combination with a furnace door of a heater comprising a casing having top and bottom members provided with pairs of Vertically alined holes, pipes extending through the casing and communicating with the several pairs of holes, and yieldable means within said casing for releasably securing the heater to said door.

6. The combination with a furnace door having a damper opening of an air heater, said heater comprising a casing having an air outlet and terminating at one end in an air inlet mouth embracing said damper opening, means for conducting the hot furnace gases through said casing, a spring clamping member housed within said casing and secured thereto, a spring clamping member at the outer side of the furnace door, and a bolt connecting said members together.

7. An air heater adapted to be attached to a furnace door and comprising a casing provided with an inlet mouth at one end with the marginal edge thereof terminating against the face of the door, means for conducting the hot combustion gases of the furnacethrough said heater, and means located.

within the inlet mouth of the heater for at taching the casing to the furnace door under tension.

8. An air heater adapted for attachment to a furnace door having a damper and comprising a casing open at its front end and having an exit for heated air at its rear end, a pair of spaced walls of said casing having a plurality of transverse passages closed to the interior of said casing for the passage of the hot ,furnace gases, and resilient means for connecting the casing centrally to the furnace door through the damper opening with the open front end of said casing embracing the damper.

9. An air heater adapted for attachment to a furnace door having a damper and comprising a casing having an air inlet mouth and an exit for heated air and provided with a transverse passage for the hot furnace gases, and means comprising a bolt and a bowed strap for connecting the casing to the furnace door with the front end of, said casing embracing the damper.

10. An air heater adapted for attachment to a furnace door having a damper and comprising a casing open at its front end and having an exit for heated air at its rear end, a pair of spaced walls of said casing having a plurality of transverse passages closed to'the interior of said casing for the passage of the hot furnace gases, a greater number of said passages being located toward the rear than toward the front of said casing, and means for connecting the casing centrally to the furnace door through the damper opening with the open front end of said casing embracing the damper.

11. A heater adapted to be attached to a furnace door and comprising an enclosing casing having top, bottom and side walls, a series of pipes ext-ending vertically through said casing, each pipe opening at the top and bottom of the casing exteriorly of the latter, and means for releasably connecting the casing to the furnace door, said .means comprising a pair of spring members located at opposite sides of the door and adapted to be held together under tension.

12. An air heater adapted for attachment to a furnace door having a damper and comprising a casing having an air inlet mouth anal an exit for heated air and provided with a tiauererse n age for the hot furaides, and meal; for connecting the to the furnace door through the dainpe'r opening with the front end of said casing embracing the damper and compri ing a bolt extending through the door and a bowed resilient clan'iping member carried by said bolt and engaging said door.

13. The combination with a furnace door having a damper opening of an air heater, said heater comprising a casing having an air outlet and having at one end an air inlet mouth terminating at the inner face of said door and embracing said damper opening. and means comprising a plurality of vertical ducts for conducting the hot furnace gases through said casing, said ducts being proportionately greater in number adjacentto said outlet than adjacent to said inlet.

l-i. The combination with a furnace door having a damper opening of an air heater, said heater con'iprising a casing having an air outlet and having at one end an air inlet mouth terminating at the inner face of said door and embracing said damper opening, means comprising a plurality of vertical ducts for conducting the hot furnace gases through said casing, and means extending through said damper opening and connected to the casing interiorly thereof for attaching the casing to said door.

Signed at 1822 Park Row Building New York New York, this 26th day of December, 1924.

HARRY A. IVES. 

